In-situ ozone cure for radical-component cvd

ABSTRACT

Methods of forming a dielectric layer are described. The methods include the steps of mixing a silicon-containing precursor with a plasma effluent, and depositing a silicon-and-nitrogen-containing layer on a substrate. The silicon-and-nitrogen-containing layer is converted to a silicon-and-oxygen-containing layer by curing in an ozone-containing atmosphere in the same substrate processing region used for depositing the silicon-and-nitrogen-containing layer. Another silicon-and-nitrogen-containing layer may be deposited on the silicon-and-oxygen-containing layer and the stack of layers may again be cured in ozone all without removing the substrate from the substrate processing region. After an integral multiple of dep-cure cycles, the conversion of the stack of silicon-and-oxygen-containing layers may be annealed at a higher temperature in an oxygen-containing environment.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Prov. Pat. App. No.61/293,082 filed Jan. 7, 2010, and titled “IN-SITU OZONE CURE FORRADICAL-COMPONENT CVD,” which is entirely incorporated herein byreference for all purposes.

BACKGROUND OF THE INVENTION

Semiconductor device geometries have dramatically decreased in sizesince their introduction several decades ago. Modern semiconductorfabrication equipment routinely produces devices with 45 nm, 32 nm, and28 nm feature sizes, and new equipment is being developed andimplemented to make devices with even smaller geometries. The decreasingfeature sizes result in structural features on the device havingdecreased spatial dimensions. The widths of gaps and trenches on thedevice narrow to a point where the aspect ratio of gap depth to itswidth becomes high enough to make it challenging to fill the gap withdielectric material. The depositing dielectric material is prone to clogat the top before the gap completely fills, producing a void or seam inthe middle of the gap.

Over the years, many techniques have been developed to avoid havingdielectric material clog the top of a gap, or to “heal” the void or seamthat has been formed. One approach has been to start with highlyflowable precursor materials that may be applied in a liquid phase to aspinning substrate surface (e.g., SOG deposition techniques). Theseflowable precursors can flow into and fill very small substrate gapswithout forming voids or weak seams. However, once these highly flowablematerials are deposited, they have to be hardened into a soliddielectric material.

In many instances, the hardening process includes a heat treatment toremove carbon and hydroxyl groups from the deposited material to leavebehind a solid dielectric such as silicon oxide. Unfortunately, thedeparting carbon and hydroxyl species often leave behind pores in thehardened dielectic that reduce the quality of the final material. Inaddition, the hardening dielectric also tends to shrink in volume, whichcan leave cracks and spaces at the interface of the dielectric and thesurrounding substrate. In some instances, the volume of the hardeneddielectric can decrease by 40% or more.

Thus, there is a need for new deposition processes and materials to formdielectric materials on structured substrates without generating voids,seams, or both, in substrate gaps and trenches. There is also a need formaterials and methods of hardening flowable dielectric materials withfewer pores and a lower decrease in volume. This and other needs areaddressed in the present application.

BRIEF SUMMARY OF THE INVENTION

Methods of forming a dielectric layer are described. The methods includethe steps of mixing a silicon-containing precursor with a plasmaeffluent, and depositing a silicon-and-nitrogen-containing layer on asubstrate. The silicon-and-nitrogen-containing layer is converted to asilicon-and-oxygen-containing layer by curing in an ozone-containingatmosphere in the same substrate processing region used for depositingthe silicon-and-nitrogen-containing layer. Anothersilicon-and-nitrogen-containing layer may be deposited on thesilicon-and-oxygen-containing layer and the stack of layers may again becured in ozone all without removing the substrate from the substrateprocessing region. After an integral multiple of dep-cure cycles, theconversion of the stack of silicon-and-oxygen-containing layers may beannealed at a higher temperature in an oxygen-containing environment.

Embodiments of the invention include methods of forming asilicon-and-oxygen-containing layer on a substrate in a substrateprocessing region in a substrate processing chamber. The methods includeforming a silicon-and-nitrogen-containing layer on the substrate in thesubstrate processing region. Forming the silicon-and-nitrogen-containinglayer involves flowing a nitrogen-and-hydrogen-containing gas into aplasma region to produce a radical-nitrogen precursor, combining acarbon-free silicon-containing precursor with the radical-nitrogenprecursor in the plasma-free substrate processing region, and depositinga silicon-and-nitrogen-containing layer on the substrate. The methodsfurther include curing the silicon-and-nitrogen-containing layer in anozone-containing atmosphere in the substrate processing region.

Additional embodiments and features are set forth in part in thedescription that follows, and in part will become apparent to thoseskilled in the art upon examination of the specification or may belearned by the practice of the invention. The features and advantages ofthe invention may be realized and attained by means of theinstrumentalities, combinations, and methods described in thespecification.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings wherein like reference numerals are usedthroughout the several drawings to refer to similar components. In someinstances, a sublabel is associated with a reference numeral and followsa hyphen to denote one of multiple similar components. When reference ismade to a reference numeral without specification to an existingsublabel, it is intended to refer to all such multiple similarcomponents.

FIG. 1 is a flowchart illustrating selected steps for making a siliconoxide film according to embodiments of the invention.

FIG. 2 is another flowchart illustrating selected steps for forming asilicon oxide film in a substrate gap according to embodiments of theinvention.

FIG. 3 is a graph of FTIR spectra acquired from silicon-containing filmsaccording to embodiments of the invention.

FIG. 4 shows a substrate processing system according to embodiments ofthe invention.

FIG. 5A shows a substrate processing chamber according to embodiments ofthe invention.

FIG. 5B shows a showerhead of a substrate processing chamber accordingto embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Methods of forming a dielectric layer are described. The methods includethe steps of mixing a silicon-containing precursor with a plasmaeffluent, and depositing a silicon-and-nitrogen-containing layer on asubstrate. The silicon-and-nitrogen-containing layer is converted to asilicon-and-oxygen-containing layer by curing an ozone-containingatmosphere in the same substrate processing region used for depositingthe silicon-and-nitrogen-containing layer. Anothersilicon-and-nitrogen-containing layer may be deposited on thesilicon-and-oxygen-containing layer and the stack of layers may again becured in ozone all without removing the substrate from the substrateprocessing region. After an integral multiple of dep-cure cycles, theconversion of the stack of silicon-and-oxygen-containing layers may beannealed at a higher temperature in an oxygen-containing environment.

Without binding the coverage of the claims to hypothetical mechanismswhich may or may not be entirely correct, a discussion of some detailsmay prove beneficial. Exposing an as-depositedsilicon-and-nitrogen-containing film to ozone while maintaining arelatively low substrate temperature increases the oxygen content overonly annealing the substrate at a relatively high substrate temperaturein an oxygen-containing environment. This may result from the relativelyopen network produced by the deposition of the silicon-and-nitrogen filmby mixing a radical-nitrogen precursor with an carbon-freesilicon-and-nitrogen-containing precursor. The open network may allowthe ozone to penetrate more deeply within the film, extending the oxideconversion in the direction of the substrate. Performing the conversionat high temperature may close the network near the surface therebylimiting the physical extent of the conversion.

The reactivity of ozone lies between that of molecular oxygen and atomicoxygen. Molecular oxygen requires a higher temperature to activate theoxidation which results in a closure of the open silicon-and-nitrogennetwork near the surface. This closure undesirably limits the oxidationin deeper portions of the silicon-and-nitrogen-containing layer. Atomicoxygen would react too readily at low temperatures and close the networkas well. Ozone is found to offer the stability to penetrate deep intothe open network while not requiring a high temperature to promote theoxidation. Additional details about the methods and systems of formingthe silicon oxide layer will now be described.

In light of the theorized ability of ozone to supplant hydrogen andnitrogen, it appeared possible to conduct the ozone cure with little orno heating enabling the ozone cure to occur within the depositionregion. Additional details about the methods and system of formingsilicon oxide using an integrated ozone-cure will now be described.

Exemplary Silicon Oxide Formation Process

FIG. 1 is a flowchart showing selected steps in methods 100 of makingsilicon oxide films according to embodiments of the invention. Themethod 100 includes providing a carbon-free silicon precursor to asubstrate processing region 102. The carbon-free silicon precursor maybe, for example, a silicon-and-nitrogen precursor, asilicon-and-hydrogen precursor, or asilicon-nitrogen-and-hydrogen-containing precursor, among other classesof silicon precursors. The silicon-precursor may be oxygen-free inaddition to carbon-free. The lack of oxygen results in a lowerconcentration of silanol (Si—OH) groups in the silicon-and-nitrogenlayer formed from the precursors. Excess silanol moieties in thedeposited film can cause increased porosity and shrinkage during postdeposition steps that remove the hydroxyl (—OH) moieties from thedeposited layer.

Specific examples of carbon-free silicon precursors may includesilyl-amines such as H₂N(SiH₃), HN(SiH₃)₂, and N(SiH₃)₃, among othersilyl-amines. The flow rates of a silyl-amine may be greater than orabout 200 sccm, greater than or about 300 sccm or greater than or about500 sccm in different embodiments. All flow rates given herein refer toa dual chamber substrate processing system. Single wafer systems wouldrequire half these flow rates and other wafer sizes would require flowrates scaled by the processed area. These silyl-amines may be mixed withadditional gases that may act as carrier gases, reactive gases, or both.Examples of the additional gases may include H₂, N₂, NH₃, He, and Ar,among other gases. Examples of carbon-free silicon precursors may alsoinclude silane (SiH₄) either alone or mixed with other silicon (e.g.,N(SiH₃)₃), hydrogen (e.g., H₂), and/or nitrogen (e.g., N₂, NH₃)containing gases. Carbon-free silicon precursors may also includedisilane, trisilane, even higher-order silanes, and chlorinated silanes,alone or in combination with one another or the previously mentionedcarbon-free silicon precursors. Generally speaking silicon precursorswhich include carbon may also be used with the caveat that the films mayshrink more than when carbon-free silicon precursors are used.

A radical-nitrogen precursor may also be provided to the substrateprocessing region 104. The radical-nitrogen precursor is anitrogen-radical-containing precursor that was generated outside thesubstrate processing region from a more stable nitrogen precursor. Forexample, a stable nitrogen precursor compound containing NH₃, H₂ and/orN₂ may be activated in a chamber plasma region or a remote plasma system(RPS) outside the processing chamber to form the radical-nitrogenprecursor, which is then transported into the substrate processingregion. The flow rate of the stable nitrogen precursor may be greaterthan or about 300 sccm, greater than or about 500 sccm or greater thanor about 700 sccm in different embodiments. The radical-nitrogenprecursor produced in the chamber plasma region may be one or more of.N, .NH, .NH₂, etc., and may also be accompanied by ionized speciesformed in the plasma.

Generally speaking, other radical precursors may be used to createsilicon-and-nitrogen-containing layers. The radical precursors may ormay not include nitrogen. If no nitrogen is present in the radicalprecursor, nitrogen will be supplied by the silicon-containingprecursor. Nitrogen may be present in both, in embodiments of theinvention. As a result of this flexibility, a radical precursor may bemore generally referred to as plasma effluents. Similarly, the stablenitrogen precursor flowed into the plasma region to create the plasmaeffluents may be generally referred to herein as a stable gas (sincenitrogen may or may not be present).

In embodiments employing a chamber plasma region, the radical-nitrogenprecursor is generated in a section of the substrate processing regionpartitioned from a deposition region where the precursors mix and reactto deposit the silicon-and-nitrogen layer on a deposition substrate(e.g., a semiconductor wafer). The radical-nitrogen precursor may alsobe accompanied by a carrier gas such as hydrogen (H₂), nitrogen (N₂),helium, etc. The substrate processing region may be described herein as“plasma-free” during the growth of the silicon-and-nitrogen-containinglayer and during the low temperature ozone cure. “Plasma-free” does notnecessarily mean the region is devoid of plasma. The borders of theplasma in the chamber plasma region are hard to define and may encroachupon the substrate processing region through the apertures in theshowerhead. In the case of inductively-coupled plasma, a small amount ofionization may be effected within the substrate processing regiondirectly. Furthermore, a low intensity plasma may be created in thesubstrate processing region without eliminating the flowable nature ofthe forming film. All causes for a plasma having much lower intensityion density than the chamber plasma region during the creation of theradical nitrogen precursor do not deviate from the scope of“plasma-free” as used herein.

In the substrate processing region, the carbon-free silicon precursorand the radical-nitrogen precursor mix and react to deposit asilicon-and-nitrogen-containing film on the deposition substrate 106.The deposited silicon-and-nitrogen-containing film may depositconformally with some recipe combinations in embodiments. In otherembodiments, the deposited silicon-and-nitrogen-containing film hasflowable characteristics unlike conventional silicon nitride (Si₃N₄)film deposition techniques. The flowable nature of the formation allowsthe film to flow into narrow gaps trenches and other structures on thedeposition surface of the substrate. Generally speaking, higherradical-nitrogen fluxes result in conformal deposition while lowerfluxes result in a flowable deposition.

The flowability may be due to a variety of properties which result frommixing a radical-nitrogen precursors with carbon-free silicon precursor.These properties may include a significant hydrogen component in thedeposited film and/or the presence of short chained polysilazanepolymers. These short chains grow and network to form more densedielectric material during and after the formation of the film. Forexample the deposited film may have a silazane-type, Si—NH—Si backbone(i.e., a Si—N—H film). When both the silicon precursor and theradical-nitrogen precursor are carbon-free, the depositedsilicon-and-nitrogen-containing film is also substantially carbon-free.Of course, “carbon-free” does not necessarily mean the film lacks eventrace amounts of carbon. Carbon contaminants may be present in theprecursor materials that find their way into the depositedsilicon-and-nitrogen precursor. The amount of these carbon impuritieshowever are much less than would be found in a silicon precursor havinga carbon moiety (e.g., TEOS, TMDSO, etc.).

Following the deposition of the silicon-and-nitrogen-containing layer,the deposition substrate may be cured in an ozone-containing atmosphere108. The post-deposition substrate remains in the same substrateprocessing region for curing. The curing temperature of the substratemay be about the same as the temperature of the substrate duringformation of the silicon-and-nitrogen-containing film in order tomaintain throughput. Alternatively, the temperature may be elevatedduring the curing operation by raising the substrate closer to a heatedfaceplate or showerhead. The temperature of the substrate during thecuring operation may be less than 120° C., less than 100° C., less than90° C., less than 80° C. or less than 70° C. in different embodiments.The temperature of the substrate may be greater than the substratetemperature during deposition, greater than 50° C., greater than 60° C.,greater than 70° C. or greater than 80° C. in different embodiments. Anyof the upper bounds may be combined with any of the lower bounds to formadditional ranges for the substrate temperature according to additionaldisclosed embodiments.

The substrate processing region may be plasma-free during the curingoperation in order to avoid creating a relatively high concentration ofatomic oxygen. A presence of atomic oxygen may prematurely close therelatively open network of the silicon-and-nitrogen-containing layer. Noplasma is present in the substrate processing region, in embodiments, toavoid generating atomic oxygen which may close the near surface networkand thwart subsurface oxidation. The flow rate of the ozone into thesubstrate processing region during the cure step may be greater than orabout 200 sccm, greater than or about 300 sccm or greater than or about500 sccm. The partial pressure of ozone during the cure step may begreater than or about 10 Torr, greater than or about 20 Torr or greaterthan or about 40 Torr. Under some conditions (e.g. between substratetemperatures from about 100° C. to about 200° C.) the conversion hasbeen found to be substantially complete so a relatively high temperatureanneal in an oxygen-containing environment may be unnecessary inembodiments.

Performing the curing operation in the same substrate processing regionmakes multiple dep-cure cycles possible, reducing the thickness requiredduring each cycle. In this embodiment, the curing operation only needsto convert a reduced thickness of silicon-and-nitrogen-containing layer.This relaxes the requirements on the ozone-containing environment,allows greater concentration of atomic oxygen and widens the substratetemperature process window. A plasma is present during the curingportion of the dep-cure cycle in some embodiments. In other embodiments,no plasma is present in the substrate processing region and theozone-containing environment contains only a small concentration ofatomic oxygen. The thickness of the layer ofsilicon-and-nitrogen-containing layer before curing may be below 1500Å,below 1000Å, below 750Å or below 500Å in different embodiments. Thethickness of the stack of all silicon-and-oxygen-containing layerscombined resulting from multiple dep-cure cycles may be between 400Å and10,000Å, in embodiments, depending primarily on the application.

A decision is made 109 as to whether the target total thickness has beenreached. If the target has not been reached, another depositionoperation (102-106) and another curing operation (108) are completed insequence before the thickness of the silicon-and-oxygen-containing filmis again compared to the target thickness. Once the target is reached,the substrate may remain or be removed from the substrate processingchamber and transferred to an annealing chamber for further conversionto silicon oxide.

Following an integral number of dep-cure cycles, the depositionsubstrate may be annealed in an oxygen-containing atmosphere 110. Thedeposition substrate may remain in the same substrate processing regionused for curing when the oxygen-containing atmosphere is introduced, orthe substrate may be transferred to a different chamber where theoxygen-containing atmosphere is introduced. The oxygen-containingatmosphere may include one or more oxygen-containing gases such asmolecular oxygen (O₂), ozone (O₃), water vapor (H₂O), hydrogen peroxide(H₂O₂) and nitrogen-oxides (NO, NO₂, etc.), among otheroxygen-containing gases. The oxygen-containing atmosphere may alsoinclude radical oxygen and hydroxyl species such as atomic oxygen (O),hydroxides (OH), etc., that may be generated remotely and transportedinto the substrate chamber. Ions of oxygen-containing species may alsobe present. The oxygen anneal temperature of the substrate may be lessthan or about 1100° C., less than or about 1000° C., less than or about900° C. or less than or about 800° C. in different embodiments. Thetemperature of the substrate may be greater than or about 500° C.,greater than or about 600° C., greater than or about 700° C. or greaterthan or about 800° C. in different embodiments. Once again, any of theupper bounds may be combined with any of the lower bounds to formadditional ranges for the substrate temperature according to additionaldisclosed embodiments.

A plasma may or may not be present in the substrate processing regionduring the oxygen anneal. The oxygen-containing gas entering the CVDchamber may include one or more compounds that have been activated(e.g., radicalized, ionized, etc.) before entering the substrateprocessing region. For example, the oxygen-containing gas may includeradical oxygen species, radical hydroxyl species, etc., activated byexposing more stable precursor compounds through a remote plasma sourceor through a chamber plasma region separated from the substrateprocessing region by a showerhead. The more stable precursors mayinclude water vapor and hydrogen peroxide (H₂O₂) that produce hydroxyl(OH) radicals and ions, and molecular oxygen and/or ozone that produceatomic oxygen (O) radicals and ions.

The oxygen-containing atmospheres of both the curing and oxygen annealprovide oxygen to convert the silicon-and-nitrogen-containing film intothe silicon oxide (SiO₂) film. As noted previously, the lack of carbonin the silicon-and-nitrogen-containing film results in significantlyfewer pores formed in the final silicon oxide film. It also results inless volume reduction (i.e., shrinkage) of the film during theconversion to the silicon oxide. For example, where asilicon-nitrogen-carbon layer formed from carbon-containing siliconprecursors may shrink by 40 vol. % or more when converted to siliconoxide, the substantially carbon-free silicon-and-nitrogen films mayshrink by about 15 vol. % or less.

Referring now to FIG. 2, another flowchart is shown illustratingselected steps in methods 200 for forming a silicon oxide film in asubstrate gap according to embodiments of the invention. The method 200may include transferring a substrate comprising a gap into a substrateprocessing region (operation 202). The substrate may have a plurality ofgaps for the spacing and structure of device components (e.g.,transistors) formed on the substrate. The gaps may have a height andwidth that define an aspect ratio (AR) of the height to the width (i.e.,H/W) that is significantly greater than 1:1 (e.g., 5:1 or more, 6:1 ormore, 7:1 or more, 8:1 or more, 9:1 or more, 10:1 or more, 11:1 or more,12:1 or more, etc.). In many instances the high AR is due to small gapwidths of that range from about 90 nm to about 22 nm or less (e.g.,about 90 nm or less, 65 nm or less, 45 nm or less, 32 nm or less, 28 nmor less, 22 nm or less, 16 nm or less, etc.).

A carbon-free silicon precursor is mixed with a radical nitrogenprecursor in the substrate processing region (operation 204). A flowablesilicon-and-nitrogen-containing layer may be deposited on the substrate(operation 206). Because the layer is flowable, it can fill gaps withhigh aspect ratios without creating voids or weak seams around thecenter of the filling material. For example, a depositing flowablematerial is less likely to prematurely clog the top of a gap before itis completely filled to leave a void in the middle of the gap.

The as-deposited silicon-and-nitrogen-containing layer may then be cured(operation 208) in the same substrate processing region used for thedeposition conducted in operations 204-206. In the pictured embodiment,multiple dep-cure cycles are not shown but may be conducted in analogousfashion to the repetition shown and described with reference to FIG. 1.If conversion is incomplete, the partially convertedsilicon-and-oxygen-containing layer is annealed in an oxygen-containingatmosphere (operation 210) to transition thesilicon-and-nitrogen-containing layer to silicon oxide. A further anneal(not shown) may be carried out in an inert environment at a highersubstrate temperature in order to densify the silicon oxide layer.

Curing and annealing the as-deposited silicon-and-nitrogen-containinglayer in an oxygen-containing atmosphere forms a silicon oxide layer onthe substrate, including the substrate gap 208. In embodiments, theprocessing parameters of operations 208 and 210 possess the same rangesdescribed with reference to operations 108 and 110 of FIG. 1. As notedabove, the silicon oxide layer has fewer pores and less volume reductionthan similar layers formed with carbon-containing precursors that havesignificant quantities of carbon present in the layer before the heattreatment step. In many cases, the volume reduction is slight enough(e.g., about 15 vol. % or less) to avoid post heat treatment steps tofill, heal, or otherwise eliminate spaces that form in the gap as aresult of the shrinking silicon oxide.

FIG. 3 is a graph of FTIR spectra acquired from silicon-containing filmsaccording to embodiments of the invention. The as-depositedsilicon-and-nitrogen-containing film 305 shows a strong peak near 908cm−1-933 cm−1 and a strong peak near 835 cm−1-860 cm−1 indicative of apresence of hydrogen and nitrogen. FTIR spectra are also shown forsilicon-and-nitrogen-containing films cured in ozone outside 310 andinside the substrate processing region 315. In both cases, the peakassociated with hydrogen is reduced similarly and other peaks matchclosely as well. This indicates that the lower temperature curing of thein-situ cure is similarly effective to curing in a dedicated chamber. AnFTIR spectrum is also shown 320 for silicon oxide processed in 8dep-cure cycles which indicates very little hydrogen and nitrogen remainin the film. The FTIR spectrum associated with multiple dep-cure cyclesalso shows a very strong oxygen peak near 1100 cm−1 indicating niceconversion of Si—H—N to silicon oxide.

Exemplary Silicon Oxide Deposition System

Deposition chambers that may implement embodiments of the presentinvention may include high-density plasma chemical vapor deposition(HDP-CVD) chambers, plasma enhanced chemical vapor deposition (PECVD)chambers, sub-atmospheric chemical vapor deposition (SACVD) chambers,and thermal chemical vapor deposition chambers, among other types ofchambers. Specific examples of CVD systems that may implementembodiments of the invention include the CENTURA ULTIMA® HDP-CVDchambers/systems, and PRODUCER® PECVD chambers/systems, available fromApplied Materials, Inc. of Santa Clara, Calif.

Examples of substrate processing chambers that can be used withexemplary methods of the invention may include those shown and describedin co-assigned U.S. Provisional Patent App. No. 60/803,499 to Lubomirskyet al, filed May 30, 2006, and titled “PROCESS CHAMBER FOR DIELECTRICGAPFILL,” the entire contents of which is herein incorporated byreference for all purposes. Additional exemplary systems may includethose shown and described in U.S. Pat. Nos. 6,387,207 and 6,830,624,which are also incorporated herein by reference for all purposes.

Embodiments of the deposition systems may be incorporated into largerfabrication systems for producing integrated circuit chips. FIG. 4 showsone such system 400 of deposition, baking and curing chambers accordingto disclosed embodiments. In the figure, a pair of FOUPs (front openingunified pods) 402 supply substrate substrates (e.g., 300 mm diameterwafers) that are received by robotic arms 404 and placed into a lowpressure holding area 406 before being placed into one of the waferprocessing chambers 408 a-f. A second robotic arm 410 may be used totransport the substrate wafers from the holding area 406 to theprocessing chambers 408 a-f and back.

The processing chambers 408 a-f may include one or more systemcomponents for depositing, annealing, curing and/or etching a flowabledielectric film on the substrate wafer. In one configuration, two pairsof the processing chamber (e.g., 408 c-d and 408 e-f) may be used todeposit the flowable dielectric material on the substrate, and the thirdpair of processing chambers (e.g., 408 a-b) may be used to anneal thedeposited dielectic. In another configuration, the same two pairs ofprocessing chambers (e.g., 408 c-d and 408 e-f) may be configured toboth deposit and anneal a flowable dielectric film on the substrate,while the third pair of chambers (e.g., 408 a-b) may be used for UV orE-beam curing of the deposited film. In still another configuration, allthree pairs of chambers (e.g., 408 a-f) may be configured to deposit andcure a flowable dielectric film on the substrate and each may beconfigured with lift pins for raising the substrate towards a heatedshowerhead, thus raising the temperature in an “integrated” curingoperation. In yet another configuration, two pairs of processingchambers (e.g., 408 c-d and 408 e-f) may be used for both deposition andUV or E-beam curing of the flowable dielectric, while a third pair ofprocessing chambers (e.g. 408 a-b) may be used for annealing thedielectric film. Any one or more of the processes described may becarried out on chamber(s) separated from the fabrication system shown indifferent embodiments.

In addition, one or more of the process chambers 408 a-f may beconfigured as a wet treatment chamber. These process chambers includeheating the flowable dielectric film in an atmosphere that includemoisture. Thus, embodiments of system 400 may include wet treatmentchambers 408 a-b and anneal processing chambers 408 c-d to perform bothwet and dry anneals on the deposited dielectric film.

FIG. 5A is a substrate processing chamber 500 according to disclosedembodiments.

A remote plasma system (RPS) 510 may process a gas which then travelsthrough a gas inlet assembly 511. Two distinct gas supply channels arevisible within the gas inlet assembly 511. A first channel 512 carries agas that passes through the remote plasma system RPS 510, while a secondchannel 513 bypasses the RPS 500. The first channel 512 may be used forthe process gas and the second channel 513 may be used for a treatmentgas in disclosed embodiments. The lid (or conductive top portion) 521and a perforated partition 553 are shown with an insulating ring 524 inbetween, which allows an AC potential to be applied to the lid 521relative to perforated partition 553. The process gas travels throughfirst channel 512 into chamber plasma region 520 and may be excited by aplasma in chamber plasma region 520 alone or in combination with RPS510. The combination of chamber plasma region 520 and/or RPS 510 may bereferred to as a remote plasma system herein. The perforated partition(also referred to as a showerhead) 553 separates chamber plasma region520 from a substrate processing region 570 beneath showerhead 553.Showerhead 553 allows a plasma present in chamber plasma region 520 toavoid directly exciting gases in substrate processing region 570, whilestill allowing excited species to travel from chamber plasma region 520into substrate processing region 570.

Showerhead 553 is positioned between chamber plasma region 520 andsubstrate processing region 570 and allows plasma effluents (excitedderivatives of precursors or other gases) created within chamber plasmaregion 520 to pass through a plurality of through holes 556 thattraverse the thickness of the plate. The showerhead 553 also has one ormore hollow volumes 551 which can be filled with a precursor in the formof a vapor or gas (such as a silicon-containing precursor) and passthrough small holes 555 into substrate processing region 570 but notdirectly into chamber plasma region 520. Showerhead 553 is thicker thanthe length of the smallest diameter 550 of the through-holes 556 in thisdisclosed embodiment. In order to maintain a significant concentrationof excited species penetrating from chamber plasma region 520 tosubstrate processing region 570, the length 526 of the smallest diameter550 of the through-holes may be restricted by forming larger diameterportions of through-holes 556 part way through the showerhead 553. Thelength of the smallest diameter 550 of the through-holes 556 may be thesame order of magnitude as the smallest diameter of the through-holes556 or less in disclosed embodiments.

In the embodiment shown, showerhead 553 may distribute (via throughholes 556) process gases which contain oxygen, hydrogen and/or nitrogenand/or plasma effluents of such process gases upon excitation by aplasma in chamber plasma region 520. In embodiments, the process gasintroduced into the RPS 510 and/or chamber plasma region 520 throughfirst channel 512 may contain one or more of oxygen (O₂), ozone (O₃),N₂O, NO, NO₂, NH₃, N_(x)H_(y) including N₂H₄, silane, disilane, TSA andDSA. The process gas may also include a carrier gas such as helium,argon, nitrogen (N₂), etc. The second channel 513 may also deliver aprocess gas and/or a carrier gas, and/or a film-curing gas used toremove an unwanted component from the growing or as-deposited film.Plasma effluents may include ionized or neutral derivatives of theprocess gas and may also be referred to herein as a radical-oxygenprecursor and/or a radical-nitrogen precursor referring to the atomicconstituents of the process gas introduced. Showerhead 553 may be heateddirectly (resistively or using a thermal transfer fluid passed throughan embedded channel) or indirectly from a plasma in chamber plasmaregion 520. Either way, the substrate temperature may be raised duringan integrated cure step by raising the substrate closer to heatedshowerhead 553 and then lowering it once the curing operation iscomplete.

In embodiments, the number of through-holes 556 may be between about 60and about 2000. Through-holes 556 may have a variety of shapes but aremost easily made round. The smallest diameter 550 of through holes 556may be between about 0.5 mm and about 20 mm or between about 1 mm andabout 6 mm in disclosed embodiments. There is also latitude in choosingthe cross-sectional shape of through-holes, which may be made conical,cylindrical or a combination of the two shapes. The number of smallholes 555 used to introduce a gas into substrate processing region 570may be between about 100 and about 5000 or between about 500 and about2000 in different embodiments. The diameter of the small holes 555 maybe between about 0.1 mm and about 2 mm.

FIG. 5B is a bottom view of a showerhead 553 for use with a processingchamber according to disclosed embodiments. Showerhead 553 correspondswith the showerhead shown in FIG. 5A. Through-holes 556 are depictedwith a larger inner-diameter (ID) on the bottom of showerhead 553 and asmaller ID at the top. Small holes 555 are distributed substantiallyevenly over the surface of the showerhead, even amongst thethrough-holes 556 which helps to provide more even mixing.

An exemplary film is created on a substrate supported by a pedestal (notshown) within substrate processing region 570 when plasma effluentsarriving through through-holes 556 in showerhead 553 combine with asilicon-containing precursor arriving through the small holes 555originating from hollow volumes 551. Though substrate processing region570 may be equipped to support a plasma for other processes such ascuring, no plasma is present during the growth of the exemplary film.

A plasma may be ignited either in chamber plasma region 520 aboveshowerhead 553 or substrate processing region 570 below showerhead 553.A plasma is present in chamber plasma region 520 to produce the radicalnitrogen precursor from an inflow of a nitrogen-and-hydrogen-containinggas. An AC voltage typically in the radio frequency (RF) range isapplied between the conductive top portion 521 of the processing chamberand showerhead 553 to ignite a plasma in chamber plasma region 520during deposition. An RF power supply generates a high RF frequency of13.56 MHz but may also generate other frequencies alone or incombination with the 13.56 MHz frequency.

The top plasma may be left at low or no power when the bottom plasma inthe substrate processing region 570 is turned on to either cure a filmor clean the interior surfaces bordering substrate processing region570. A plasma in substrate processing region 570 is ignited by applyingan AC voltage between showerhead 553 and the pedestal or bottom of thechamber. A cleaning gas may be introduced into substrate processingregion 570 while the plasma is present.

The pedestal may have a heat exchange channel through which a heatexchange fluid flows to control the temperature of the substrate. Thisconfiguration allows the substrate temperature to be cooled or heated tomaintain relatively low temperatures (from room temperature throughabout 120° C.). The heat exchange fluid may comprise ethylene glycol andwater. The wafer support platter of the pedestal (preferably aluminum,ceramic, or a combination thereof) may also be resistively heated inorder to achieve relatively high temperatures (from about 120° C.through about 1100° C.) using an embedded single-loop embedded heaterelement configured to make two full turns in the form of parallelconcentric circles. An outer portion of the heater element may runadjacent to a perimeter of the support platter, while an inner portionruns on the path of a concentric circle having a smaller radius. Thewiring to the heater element passes through the stem of the pedestal.

The substrate processing system is controlled by a system controller. Inan exemplary embodiment, the system controller includes a hard diskdrive, a floppy disk drive and a processor. The processor contains asingle-board computer (SBC), analog and digital input/output boards,interface boards and stepper motor controller boards. Various parts ofCVD system conform to the Versa Modular European (VME) standard whichdefines board, card cage, and connector dimensions and types. The VMEstandard also defines the bus structure as having a 16-bit data bus anda 24-bit address bus.

The system controller controls all of the activities of the CVD machine.The system controller executes system control software, which is acomputer program stored in a computer-readable medium. Preferably, themedium is a hard disk drive, but the medium may also be other kinds ofmemory. The computer program includes sets of instructions that dictatethe timing, mixture of gases, chamber pressure, chamber temperature, RFpower levels, susceptor position, and other parameters of a particularprocess. Other computer programs stored on other memory devicesincluding, for example, a floppy disk or other another appropriatedrive, may also be used to instruct the system controller.

A process for depositing a film stack on a substrate or a process forcleaning a chamber can be implemented using a computer program productthat is executed by the system controller. The computer program code canbe written in any conventional computer readable programming language:for example, 68000 assembly language, C, C++, Pascal, Fortran or others.Suitable program code is entered into a single file, or multiple files,using a conventional text editor, and stored or embodied in a computerusable medium, such as a memory system of the computer. If the enteredcode text is in a high level language, the code is compiled, and theresultant compiler code is then linked with an object code ofprecompiled Microsoft Windows® library routines. To execute the linked,compiled object code the system user invokes the object code, causingthe computer system to load the code in memory. The CPU then reads andexecutes the code to perform the tasks identified in the program.

The interface between a user and the controller is via a flat-paneltouch-sensitive monitor. In the preferred embodiment two monitors areused, one mounted in the clean room wall for the operators and the otherbehind the wall for the service technicians. The two monitors maysimultaneously display the same information, in which case only oneaccepts input at a time. To select a particular screen or function, theoperator touches a designated area of the touch-sensitive monitor. Thetouched area changes its highlighted color, or a new menu or screen isdisplayed, confirming communication between the operator and thetouch-sensitive monitor. Other devices, such as a keyboard, mouse, orother pointing or communication device, may be used instead of or inaddition to the touch-sensitive monitor to allow the user to communicatewith the system controller.

As used herein “substrate” may be a support substrate with or withoutlayers formed thereon. The support substrate may be an insulator or asemiconductor of a variety of doping concentrations and profiles andmay, for example, be a semiconductor substrate of the type used in themanufacture of integrated circuits. A layer of “silicon oxide” mayinclude minority concentrations of other elemental constituents such asnitrogen, hydrogen, carbon and the like. In some embodiments of theinvention, silicon oxide consists essentially of silicon and oxygen. Agas in an “excited state” describes a gas wherein at least some of thegas molecules are in vibrationally-excited, dissociated and/or ionizedstates. A gas (or precursor) may be a combination of two or more gases(precursors). The term “trench” is used throughout with no implicationthat the etched geometry has a large horizontal aspect ratio. Viewedfrom above the surface, trenches may appear circular, oval, polygonal,rectangular, or a variety of other shapes. The term “via” is used torefer to a low aspect ratio trench which may or may not be filled withmetal to form a vertical electrical connection. The term “precursor” isused to refer to any process gas (or vaporized liquid droplet) whichtakes part in a reaction to either remove or deposit material from asurface.

Having described several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theinvention. Additionally, a number of well-known processes and elementshave not been described in order to avoid unnecessarily obscuring thepresent invention. Accordingly, the above description should not betaken as limiting the scope of the invention.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassed.The upper and lower limits of these smaller ranges may independently beincluded or excluded in the range, and each range where either, neitheror both limits are included in the smaller ranges is also encompassedwithin the invention, subject to any specifically excluded limit in thestated range. Where the stated range includes one or both of the limits,ranges excluding either or both of those included limits are alsoincluded.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a process” includes aplurality of such processes and reference to “the precursor” includesreference to one or more precursor and equivalents thereof known tothose skilled in the art, and so forth.

Also, the words “comprise,” “comprising,” “include,” “including,” and“includes” when used in this specification and in the following claimsare intended to specify the presence of stated features, integers,components, or steps, but they do not preclude the presence or additionof one or more other features, integers, components, steps, acts, orgroups.

1. A method of forming a silicon-and-oxygen-containing layer on asubstrate in a substrate processing region in a substrate processingchamber, the method comprising: forming asilicon-and-nitrogen-containing layer on the substrate in the substrateprocessing region, wherein forming the silicon-and-nitrogen-containinglayer comprises: flowing a stable gas into a plasma region to produceplasma effluents, combining a silicon-containing precursor with theplasma effluents in the plasma-free substrate processing region, anddepositing a silicon-and-nitrogen-containing layer on the substrate; andcuring the silicon-and-nitrogen-containing layer in an ozone-containingatmosphere in the substrate processing region to form thesilicon-and-oxygen-containing layer.
 2. The method of claim 1 furthercomprising forming a second silicon-and-nitrogen-containing layer on thesubstrate in the substrate processing region, wherein forming the secondsilicon-and-nitrogen-containing layer comprises: flowing the stable gasinto the plasma region to produce plasma effluents, combining asilicon-containing precursor with the plasma effluents in the substrateprocessing region, and depositing the secondsilicon-and-nitrogen-containing layer on the substrate in the substrateprocessing region; and curing the second silicon-and-nitrogen-containinglayer in an ozone-containing atmosphere in the substrate processingregion.
 3. The method of claim 1 wherein the substrate processing regionis plasma-free during the operation of forming thesilicon-and-nitrogen-containing layer to avoid direct plasma-excitationof the silicon-containing precursor.
 4. The method of claim 1 whereinthe substrate processing region is plasma-free during the operation ofcuring the silicon-and-nitrogen-containing layer.
 5. The method of claim1 wherein a substrate temperature during the curing operation is lessthan 50° C. higher than during the operation of depositing thesilicon-and-nitrogen-containing layer.
 6. The method of claim 1 whereina substrate temperature during the operation of depositing thesilicon-and-nitrogen-containing layer is less than 100° C.
 7. The methodof claim 1 wherein a substrate temperature during the curing operationis less than 200° C.
 8. The method of claim 1 wherein a thickness of thesilicon-and-nitrogen-containing layer is less than or about 1500Å. 9.The method of claim 1 wherein the substrate is raised towards a heatedshowerhead to heat the substrate during the curing operation.
 10. Themethod of claim 1 wherein the stable gas is anitrogen-and-hydrogen-containing gas and the plasma effluents comprise aradical-nitrogen precursor.
 11. The method of claim 10 wherein thenitrogen-and-hydrogen-containing gas comprises ammonia.
 12. The methodof claim 1 wherein the silicon-containing precursor is carbon-free. 13.The method of claim 1 wherein the silicon-containing precursor comprisesa silicon-and-nitrogen-containing precursor.
 14. The method of claim 1wherein the silicon-containing precursor comprises N(SiH₃)₃.
 15. Themethod of claim 1 wherein the silicon-and-nitrogen-containing layercomprises a carbon-free Si—N—H layer.
 16. The method of claim 1 furthercomprising raising a temperature of the substrate to an oxygen annealtemperature above or about 600° C. in an oxygen-containing atmosphereafter the curing operation.
 17. The method of claim 16 wherein theoxygen-containing atmosphere comprises one or more gases selected fromthe group consisting of atomic oxygen, ozone, and steam (H₂O).
 18. Themethod of claim 1 wherein the substrate is patterned and has a trenchhaving a width of about 45 nm or less, and wherein the silicon oxidelayer formed in the trench is substantially void-free.
 19. The method ofclaim 1 wherein the plasma region is in a remote plasma system.
 20. Themethod of claim 1 wherein the plasma region is a partitioned portion ofthe substrate processing chamber separated from the plasma-freesubstrate processing region by a showerhead.